An inflatable vehicle occupant protection device, such as an air bag, is part of an apparatus which further includes a collision sensor and an inflator. When the collision sensor senses a vehicle collision having at least a predetermined threshold level of severity, the inflator is actuated. The inflator then emits inflation fluid which inflates the air bag into the vehicle occupant compartment to help protect an occupant of the vehicle.
An air bag and an inflator are typically assembled together as parts of an air bag module which is separate from the collision sensor. The air bag module is located in the vehicle adjacent to the vehicle occupant compartment. For example, an air bag module may be located on the vehicle steering column or in the vehicle instrument panel. An air bag module may also be located in a side portion of the vehicle, such as a door panel, or in another part of the vehicle, such as the roof, the floor, or a seat.
An inflator in an air bag module commonly has an elongated cylindrical shape. An air bag module including such an inflator may also include an elongated, tubular diffuser which contains the inflator. The diffuser typically has a row of radially projecting mounting studs for mounting the air bag module in the vehicle. When the air bag module is assembled and installed in the vehicle, the diffuser and the inflator are contained together within an inlet portion of the air bag. The mounting studs project outward through a corresponding row of apertures in the inlet portion of the air bag.
When the inflator is actuated, the diffuser directs the inflation fluid to flow from the inlet portion of the air bag to a larger, inflatable body portion of the air bag. The inflation fluid inflates the body portion of the air bag into the vehicle occupant compartment to help protect an occupant of the vehicle.